Priming valve for a centrifugal pump



7, 1956 R. A. HILL ETAL 2,757,616

PRIMING VALVE FOR ,A CENTRIFUGAL PUMP Filed Jan. 21, 1953 5 E \\l//m ll 1 0 gm INVENTOR.

Robe/"f 14. #1?! BY David F Thomas 0% m'DJnn ATTORNEY be proportioned so as to be limited in upward movement by engagement against the offset 39 of the valve housing; and the cotter pin 53 and washer 54 eliminated.

The priming pump may be connected to the discharge manifold, the volute, or at any other suitable location, such as to the impeller intake chamber. When it is desired to use the centrifugal pump A and if no priming water is found in the system, the priming pump 21 is placed into operation to evacuate air from the discharge manifold and accordingly from the volutes of the pump. This acts to draw Water in through one or both of the inlets 10 and 11 until all or most of the air has been evacuated from the centrifugal pump. During this process the valve 32 remains in the position shown in Figure 2 of the drawings, while the float ball drops onto the base of the cup-shaped portion 44 of the valve.

When the centrifugal pump is filled with water, water is drawn through the connection 24 and into the top of the valve 23. This downward force of water prevents the float valve 43 from seating and the water continues through the valve housing and through the priming connection 22 and into the priming pump 21, the water being expelled through the discharge of this priming pump 21 to atmosphere.

When the priming pump has evacuated the air from the centrifugal pump A, the priming pump 21 is usually disconnected from the source of power and the main pump is started into operation. A short interval usually elapses between the time the priming pump 21 is discontinued from the power source and the time the main centrifugal pump is connected thereto and brought up to pumping speed. During this time water normally tends to drain back through the pump inlet 10 or 11, or both, thus partially draining the priming water from the main pump.

As soon as the priming operation is completed and the priming pump 21 is turned off, the float 43 raises against its seat 42 and tends to prevent water from flowing upwardly through this valve. When thus engaged the float 43 prevents air from being drawn through the priming pump and into the centrifugal pump. Thus the float valve has a tendency to keep the priming liquid in the centrifugal pump during the interval when neither pump is functioning.

When the centrifugal pump A is started into operation in a system in which the connection 24 is connected to the discharge manifold 13, water pressure is delivered to the discharge manifold 13 accordingly to the connection 24 connecting the discharge manifold with the valve B. This water under pressure tends to flow through the valve 13 and drive the gear pump. This causes a pressure to be built up in the priming system. As the pressure on opposite sides of the valve 32 is then unbalanced because of the valve stem 31 extending through the valve casing, the valve 32 remains in closed position, preventing the escape of liquid until the main pump is cut off or loses its prime.

A similar operation takes place when the connection 24 is connected to the volute of the pump. Pressure from the volute passes through the connection 24 acting to close the valve 32 against its seat, preventing escape of liquid until the pressure drops.

When the connection 24 is connected to the pump intake, parallel connections may extend to high points of all impeller inlet chambers if the pump is of the impeller type. pressure from the second stage impeller inlet acts to close the valve 32 in the manner described. Obviously, when a plurality of connections are used in parallel check valves must be incorporated in these lines to prevent pressure from one line flowing in a reverse direction toward the centrifugal pump in the parallel line or lines.

In the event the impellers are in parallel, the valve B If the impellers are arranged in series, the

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still serves a useful purpose. When the inlet chamber is subject to partial vacuum, the float ball 43 is held in sealing position against the seat 42 during normal operation of the pump, or until it loses its prime. Under certain conditions of operation, however, the centrifugal pump is supplied from a hydrant or other water supply of water under pressure. In such an instance, the priming pump need not be used, but water could leak out through the priming pump if no means were provided to prevent such action. In such a case the hydrant pressure entering the valve B will force the valve 32 against its seat 46, preventing leakage as long as the pressure within the inlet exceeds atmospheric pressure. Subsequently, the float valve 43 rises and seals the connection when a subatmospheric pressure is attached in the pump inlet, or impeller inlet chamber.

In accordance with the patent statutes, we have described the principles of construction and operation of our priming valve for a centrifugal pump, and while it has been endeavored to set forth the best embodiments thereof, it is desired to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of the invention.

We claim:

1. A priming valve in combination with a centrifugal pump and a priming pump, the valve including a valve chamber, means connecting the lower end of said chamber to the priming pump, means connecting the upper extremity of the chamber to the interior of the centrifugal pump, a pressure valve interposed between the ends of the valve chamber for closing the lower end of said chamber when subjected to suflicient centrifugal pump pres sure, resilient means normally holding said pressure valve open, and a float valve above the level of said pressure valve and designed to close the inlet at the top of the valve chamber leading to said centrifugal pump.

2. The structure described in claim 1 and in which the pressure valve is provided with a cup-shaped upper extremity designed to accommodate the float valve.

3. The structure described in claim 1 and in which the float valve comprises a body of light weight material oi lower specific gravity than water and a liquid-proof covering therefor.

4. The structure described in claim 1 and in which the valve is provided with a cup-shaped upper extremity designed to accommodate the float valve, and said cup shaped valve end having threaded apertures therethrough.

5. A priming valve system comprising a main pump, a priming pump having inlet means, a valve chamber having a pair of openings, a float element for closing one of said openings, said one opening having connection with the interior of the main pump, a pressure valve element for closing the other of said openings, said other opening having connection with said inlet means, and means for yieldingly biasing said pressure element into spaced relation with said other opening, whereby a predetermined fluid pressure will overcome the effect of said biasing means to close said pressure element.

References Cited in the file of this patent UNITED STATES PATENTS 1,573,931 Goyne Feb. 23, 1926 1,665,460 Hollander Apr. 10, 1928 1,944,249 Lencke Ian. 23, 1934 1,995,812 Noble Mar. 26, 1935 2,282,338 Moody -c May 12, 1942 2,322,910 Adney et al June 29, 1943 2,404,924 Sacchini July 30, 1946 2,462,605 Bridwell Sept. 21, 1953 FOREIGN PATENTS 348,860 Germany Jan. 14, 1935 517,677 Great Britain Feb. 6, 1940 

